The basic stamp 2 has built in BSR module controller commands,  I See in
home automation catalogs a module with a 4 pin phone type connector made to
interface the signals to the power lines.  look at
http://www.micromint.com/plix.html they sell a custom IC that does it all
for you....

-----Original Message-----
From: Alberto Smulders <insad@ITACOM.COM.PY>
To: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
Date: Friday, September 26, 1997 12:35 AM
Subject: Data transmission over power lines



>Hello,
>
>For remote sensing and controlling in a greenhouse, we want to use
>bi-directional data transmission over power lines, using very cheap
>hardware (microcontroller eventually with incorporated ADC and
>relays/triacs for controlling stuff), so we can chatter around small "black
>boxes" in the greenhouse where we need them, without lots of dedicated
>wiring to a central controller; all the "black boxes" under control by a
>central PC running Win95 or (maybe) Win NT.
>Generating FSK signals with the same microcontroller must be easy
>(frequency is low, around 100 kHz for power line data transmission).
>But is it possible also to use the microcontroller for filtering/decoding
>the signals, without using dedicated extra hardware?
>Any ideas - suggestions - critics - experiences - stories on frustrations
>(or not) - are welcome.
>Thanks....
>
>Albert A. Smulders
>InSAD - Encarnacion, Paraguay
>South America
>insad@itacom.com.py